[LTP] [PATCH v2] syscalls/futex_waitv0[23]: replace TST_THREAD_STATE_WAIT with repeated wake

[Jan Stancek]

TST_THREAD_STATE_WAIT isn't reliable to tell that it's safe to
call futex_wake(). futex_wake() can be called prematurely and
return 0, which leaves other thread timing out.

Replace it with repeated futex_wake() until it fails or wakes at least 1 waiter.
Also extend timeout to 5 seconds to avoid false positives from systems with
high steal time (e.g. overloaded s390x host).

For futex_waitv03 this replaces while loop with TST_RETRY_FUNC.

Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
 .../kernel/syscalls/futex/futex_waitv02.c     | 21 ++++++-------------
 .../kernel/syscalls/futex/futex_waitv03.c     | 12 +++--------
 testcases/kernel/syscalls/futex/futextest.h   | 15 +++++++++++++
 3 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/testcases/kernel/syscalls/futex/futex_waitv02.c b/testcases/kernel/syscalls/futex/futex_waitv02.c
index 0a0e2b62075c..ccea5eb5e745 100644
--- a/testcases/kernel/syscalls/futex/futex_waitv02.c
+++ b/testcases/kernel/syscalls/futex/futex_waitv02.c
@@ -50,19 +50,13 @@ static void setup(void)
 	}
 }
 
-static void *threaded(void *arg)
+static void *threaded(LTP_ATTRIBUTE_UNUSED void *arg)
 {
 	struct futex_test_variants tv = futex_variant();
-	int tid = *(int *)arg;
 
-	TST_THREAD_STATE_WAIT(tid, 'S', 0);
-
-	TEST(futex_wake(tv.fntype, (void *)(uintptr_t)waitv[numfutex - 1].uaddr,
-			1, FUTEX_PRIVATE_FLAG));
-	if (TST_RET < 0) {
-		tst_brk(TBROK | TTERRNO,
-			"futex_wake private returned: %ld", TST_RET);
-	}
+	TST_RETRY_FUNC(futex_wake(tv.fntype,
+		(void *)(uintptr_t)waitv[numfutex - 1].uaddr,
+		1, FUTEX_PRIVATE_FLAG), futex_waked_someone);
 
 	return NULL;
 }
@@ -70,16 +64,13 @@ static void *threaded(void *arg)
 static void run(void)
 {
 	struct timespec to;
-	int tid;
 	pthread_t t;
 
-	tid = tst_syscall(__NR_gettid);
-
-	SAFE_PTHREAD_CREATE(&t, NULL, threaded, (void *)&tid);
+	SAFE_PTHREAD_CREATE(&t, NULL, threaded, NULL);
 
 	/* setting absolute timeout for futex2 */
 	SAFE_CLOCK_GETTIME(CLOCK_MONOTONIC, &to);
-	to.tv_sec++;
+	to.tv_sec += 5;
 
 	TEST(futex_waitv(waitv, numfutex, 0, &to, CLOCK_MONOTONIC));
 	if (TST_RET < 0) {
diff --git a/testcases/kernel/syscalls/futex/futex_waitv03.c b/testcases/kernel/syscalls/futex/futex_waitv03.c
index ee79728474ee..c674f52d8d4c 100644
--- a/testcases/kernel/syscalls/futex/futex_waitv03.c
+++ b/testcases/kernel/syscalls/futex/futex_waitv03.c
@@ -74,15 +74,9 @@ static void *threaded(LTP_ATTRIBUTE_UNUSED void *arg)
 {
 	struct futex_test_variants tv = futex_variant();
 
-	do {
-		TEST(futex_wake(tv.fntype, (void *)(uintptr_t)waitv[numfutex - 1].uaddr,
-			1, 0));
-		if (TST_RET < 0) {
-			tst_brk(TBROK | TTERRNO,
-				"futex_wake private returned: %ld", TST_RET);
-		}
-		usleep(1000);
-	} while (TST_RET < 1);
+	TST_RETRY_FUNC(futex_wake(tv.fntype,
+		(void *)(uintptr_t)waitv[numfutex - 1].uaddr,
+		1, 0), futex_waked_someone);
 
 	return NULL;
 }
diff --git a/testcases/kernel/syscalls/futex/futextest.h b/testcases/kernel/syscalls/futex/futextest.h
index fd10885f3205..515b5102d4fc 100644
--- a/testcases/kernel/syscalls/futex/futextest.h
+++ b/testcases/kernel/syscalls/futex/futextest.h
@@ -277,4 +277,19 @@ futex_set(futex_t *uaddr, u_int32_t newval)
 	return newval;
 }
 
+/**
+ * futex_waked_someone() - ECHCK func for TST_RETRY_FUNC
+ * @ret:	return value of futex_wake
+ *
+ * Return value drives TST_RETRY_FUNC macro.
+ */
+static inline int
+futex_waked_someone(int ret)
+{
+	if (ret < 0)
+		tst_brk(TBROK | TERRNO, "futex_wake returned: %d", ret);
+
+	return ret;
+}
+
 #endif /* _FUTEXTEST_H */
-- 
2.27.0